With the development of the semiconductor industry, integrated circuits with higher performance and more powerful functions require greater element density. Thus, the sizes of the components need to be scaled further. Accordingly, in order to improve the performance of the Metal Oxide Semiconductor Field Effect Transistor (MOSFET), the gate length of the MOSFET should be further reduced. However, with the continuous reduction of the gate length, when the gate length is reduced to approach the width of the depletion layer of the source and the drain, for example less than 40 nm, severe short channel effects (SCE) occur, which disadvantageously leads to deterioration of device performance and difficulty for large scale production of integrated circuit. It has become a challenge in large scale production of integrated circuits to reduce and effectively control the short channel effects.
A solution to improve the short channel effects by forming a steep retrograded well in the substrate may be used to alleviate the short channel effects. This solution is based on forming a steep retrograded well in a channel to decrease the width of the depletion layer under the gate and further reduce the short channel effect. Hence, it usually requires a very steep distribution for the retrograded well to achieve good effects. Rapid annealing is typically used to activate dopants and eliminate the defects caused by ion implantation to the source/drain region. The thermal budget in annealing of the source region and drain region as well as the source/drain extensions is too high, thus the temperature and time required to form atom diffusion by this annealing is much higher than that needed by annealing of the channel dopants. As a result, the dopants in channel are unfavorably overly diffused, and the distribution of the retrograded well is no longer steep.
Therefore, in order to improve the manufacture of high-performance semiconductor devices, there is a need for a method to produce steep retrograded distribution.